class Solution {
public:
    double findMedianSortedArrays(int A[], int m, int B[], int n) {
        if ((m + n) % 2 != 0)
            return findKth(A, m, B, n, (m + n + 1) / 2);
        else
            return (findKth(A, m, B, n, (m + n) / 2) + findKth(A, m, B, n, (m + n) / 2 + 1)) / 2;
    }
    
    double findKth(int A[], int m, int B[], int n, int k) {
        if (m > n) return findKth(B, n, A, m, k);
        if (m == 0) return B[k - 1];
        if (k == 1) return min(A[0], B[0]);
        int pa = min(k / 2, m), pb = k - pa;
        if (A[pa - 1] < B[pb - 1]) return findKth(A + pa, m - pa, B, n, k - pa);
        else if (A[pa - 1] > B[pb - 1]) return findKth(A, m, B + pb, n - pb, k - pb);
        else return A[pa - 1];
    }
};
